Anaemia and the gastrointestinal (GI) tract

Anaemia is a common reason for referral to any gastroenterological service. Iron-deficiency anaemia is the most frequent, making up to 13% of referrals. The type of anaemia and any clinical symptoms often delineate the most appropriate investigations. However, iron-deficiency anaemia (IDA) can be the sole reason for referral and, depending upon patient’s age, necessitates endoscopic investigation of the gastrointestinal tract (GIT). The functional definition of anaemia is a circulating red cell mass insufficient to meet tissue oxygen requirements. However, arbitrary criteria are often used to define anaemia, the most frequently used being the WHO criteria of 13 g/dl for males, 12 g/dl for non-pregnant females and 11 g/dl for pregnant women. Anaemia results from either defective production or an increased destruction or loss of cells and can be classified by red cell indices, particularly the mean cell volume. It can be divided into three main categories: microcytic, normocytic and macrocytic. In this article we will give a brief overview of the most common presentations of anaemia relevant to the GI system.